ddMd/neighbor/PairIterator.h

#ifndef DDMD_PAIR_ITERATOR_H
#define DDMD_PAIR_ITERATOR_H

/*
* Simpatico - Simulation Package for Polymeric and Molecular Liquids
*
* Copyright 2010 - 2017, The Regents of the University of Minnesota
* Distributed under the terms of the GNU General Public License.
*/

#include "PairList.h"
#include <util/global.h>

namespace DdMd
{

   using namespace Util;

   class Atom;
   
   class PairIterator
   {
   
   public:

      PairIterator();
   
      PairIterator(const PairList &pairList);
  
      // Use default C++ destructor.
 
      PairIterator& operator++ ();
 
      bool isEnd() const;
   
      bool notEnd() const;
   
      void getPair(Atom* &atom1Ptr, Atom* &atom2Ptr) const;

   private:
 
      Atom* const* atom1Ptrs_;  

      Atom* const* atom2Ptrs_;  

      const int*   first_; 

      int    nAtom1_;      
  
      int    nAtom2_;      
  
      int    atom1Id_;

      int    atom2Id_;

   // friends:

      friend class PairList;

   }; 

   /*
   * Default constructor.
   */
   inline PairIterator::PairIterator()
    : atom1Ptrs_(0),
      atom2Ptrs_(0),
      first_(0),
      nAtom1_(0),
      nAtom2_(0),
      atom1Id_(0),
      atom2Id_(0)
   {}

   /*
   * Constructor, initialized iterator.
   */
   inline PairIterator::PairIterator(const PairList &pairList)
    : atom1Ptrs_(0),
      atom2Ptrs_(0),
      first_(0),
      nAtom1_(0),
      nAtom2_(0),
      atom1Id_(0),
      atom2Id_(0)
   {  pairList.begin(*this); }

   /*
   * Get pointers to current pair of Atoms. 
   */
   inline void PairIterator::getPair(Atom* &atom1Ptr, Atom* &atom2Ptr) const
   {
      assert(atom1Id_ >=0);
      assert(atom1Id_ < nAtom1_);
      assert(atom2Id_ >=0);
      assert(atom2Id_ < nAtom2_);
      atom1Ptr = atom1Ptrs_[atom1Id_];
      atom2Ptr = atom2Ptrs_[atom2Id_];
   }
 
   /*
   * Increment current pair.
   */
   inline PairIterator& PairIterator::operator++ ()
   {
      assert(atom1Id_ >=0);
      assert(atom1Id_ < nAtom1_);
      assert(atom2Id_ >=0);
      assert(atom2Id_ < nAtom2_);
      ++atom2Id_;
      if (atom2Id_ == first_[atom1Id_+1]) {
         ++atom1Id_;
      }
      return *this;
   }

   /*
   * Return true if past last pair in list.
   */
   inline bool PairIterator::isEnd() const
   { return (atom2Id_ == nAtom2_); }
   
   /*
   * Return false if one past last pair in list.
   */
   inline bool PairIterator::notEnd() const
   { return (atom2Id_ != nAtom2_); }
   
 
 
} 
#endif